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Updated: Jul 16, 2025

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Architecture of the MKK6-p38α complex defines the basis of MAPK specificity and activation

Pauline Juyoux1, Ioannis Galdadas2,3, Dorothea Gobbo2,3

  • 1European Molecular Biology Laboratory (EMBL), Grenoble, France.

Science (New York, N.Y.)
|September 14, 2023
PubMed

Insights

Researchers modeled the activation of p38α (mitogen-activated protein kinase) by MKK6 (MAP2K). This reveals a dynamic, multistep phosphorylation mechanism crucial for immune signaling and drug development.

Area of Science:

  • Cellular signaling pathways
  • Molecular mechanisms of kinase activation
  • Protein-protein interactions in immunity

Background:

  • Mitogen-activated protein kinase (MAPK) p38α is a key regulator of inflammation and immune responses.
  • p38α is a significant drug target, but its activation mechanism by MAP2Ks remains poorly understood due to transient complex formation.

Purpose of the Study:

  • To elucidate the molecular mechanism of p38α activation by its cognate MAP2K, MKK6.
  • To generate a structural model of the p38α-MKK6 complex and understand the phosphorylation process.

Main Methods:

  • Integrated cryo-electron microscopy (cryo-EM) with molecular dynamics (MD) simulations.
  • Utilized hydrogen-deuterium exchange mass spectrometry (HDX-MS) and cellular experiments.
  • Developed a multidisciplinary approach to capture transient kinase complexes.

Main Results:

  • A dynamic, multistep phosphorylation mechanism for p38α activation was demonstrated.
  • Key catalytically relevant interactions within the p38α-MKK6 complex were identified.
  • Disordered amino termini of MAP2K were shown to dictate pathway specificity.

Conclusions:

  • The study provides unprecedented structural and mechanistic insights into a fundamental kinase-kinase phosphorylation event.
  • Understanding this activation mechanism can inform the development of targeted therapeutics for inflammatory and immune diseases.
  • MAP2K disordered regions play a critical role in regulating signaling specificity.

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